This invention is directed to a needle free access valve for use in a needle free intravenous access system, and where the valve permits bi-directional flow when open. The valve finds particular use in the medical field.
A needle free access valve is one where the valve can be opened using a needleless syringe. A needleless syringe is a syringe where the needle has been removed such that the front of the syringe has only the luer taper or luer lock. Such valves are known but suffer from a number of disadvantages. A typical known valve has a body composed of two cylindrical containers. One container has a tubular opening into which the luer taper can be pressed. The other container has a tubular opening filled with a luer lock which allows the valve to be attached to various medical devices. Fluid flows through the luer taper upon depression of the syringe plunger and flows through the valve. The valve has a circular valve disk which can be forced open by the pressure of the fluid. When the fluid pressure stops, the valve returns to its closed position. This type of arrangement is entirely conventional. One disadvantage with this arrangement is that high levels of fluid flow can often not be obtained due to the design of the valve. That is, the valve itself is solid and fluid can flow only about the edge of the valve when the valve is opened. Another disadvantage is the lack of sterilisation around the inlet part of the valve. Sterilisation is critical as different devices can be inserted into the valve. For instance, a number of different syringes or fluid connections can be connected to the inlet part of the valve. It is essential to ensure that the valve does not become contaminated. With conventional valves, the luer taper of the syringe is pressed into the inlet part of the valve to hold the syringe to the valve. When the syringe is removed, the inlet part cannot be easily cleaned due to its small size and because it has a tubular configuration and it is difficult to clean and sterilise the inside part of the tubular configuration.
Other disadvantages with conventional valves is the production costs, the relatively large number of components making up the valve, the difficulty in mass production of the valve.
The present invention is directed to a needle-free access valve which can be swabbed and sterilised between use, and which may at least partially overcome some of the abovementioned disadvantages or provide the consumer with useful or commercial choice.
In one form the invention resides in a valve assembly which has an inlet and an outlet, the inlet forming one end of a tubular passageway, a valve member which is slideable along the tubular passageway between a closed position where fluid is unable to flow through the valve assembly, and an open position, the valve member having an outer end and an inner end, and biasing means to bias the valve member to the closed position, characterised in that when the valve member is in the closed position, the outer end is substantially at the inlet of the valve assembly to close off the tubular passageway and to allow the inlet area to be sterilised.
In this manner, when the valve member is in the closed position, the outer end is typically flush with the inlet to present a flush surface which can be swabbed or sterilised. With conventional valves, the tubular passageway remains completely open as the valve is usually at the bottom of the tubular passageway, and such an open passageway is a source of contamination which is difficult if not impossible to properly sterilise.
The valve assembly may be formed from two main parts being a top casing and a bottom casing which are fixed together in a permanent seal. The top casing typically has the inlet and the tubular passageway. The bottom casing typically has the outlet which may be configured or have some form of attachment means to allow the valve to be attached to other devices. The bottom casing is typically also substantially tubular. The top casing and the bottom casing may have a stepped configuration comprising a passageway of smaller diameter or cross-section adjacent the inlet and outlet, and a passageway of larger diameter or cross-section where the two parts meet. The passageway of larger diameter or cross-section can comprise an internal chamber.
The valve member may have different configurations depending on the operation of the valve assembly. In one form, the valve assembly is made from only nonmetallic parts and the biasing means does not comprise a helical spring. In this form of the invention, the valve member can have an xe2x80x9carrow shapedxe2x80x9d configuration and may comprise a forward head part or plunger part, and a rear tail or stem part. The valve member may have at least one longitudinal passageway along which fluid can pass. The passageway may comprise an external passageway formed in the outside wall of the valve member and/or an internal passageway. Preferably, the valve member is provided with at least one longitudinal external passageway formed in the stem part of the valve member which communicates with at least one internal passageway extending through the plunger part of the valve member. In this manner, fluid can pass along and through the valve member and therefore through the valve assembly. In this form of the invention, the stem part of the valve member can be positioned in the tubular passageway which comprises the inlet, and the plunger part of the valve member can be positioned in the chamber. The valve member has an outer end and an inner end. In this form of the invention, the outer end may comprise an end wall of the stem, and the inner end may comprise a forward portion of the plunger part. A sealing means may be provided to seal the valve member against fluid flow when the valve member is in the closed position. The outer end may comprise or be associated with sealing means to seal this part of the valve member against the tubular passageway and against passage of fluid. Alternatively, or in addition thereto, the plunger part may have a sealing face which seals against part of the tubular passageway and/or an internal wall of the chamber.
A biasing means is provided to bias the valve member to the closed position. In this form of the invention, the biasing means may comprise a torsion ring which can be fitted into the chamber. The torsion ring may be provided with a plurality of finger members having one end attached to or forming part of the ring, and having the free end tapering to the free end of the other finger members. The torsion ring and the finger members are preferably configured to complement the shape of the plunger part of the valve member and function to bias the valve member to the closed position.
In a second embodiment, the valve assembly has a helical spring which comprise the biasing means, and the valve member is formed from two parts which can comprise a stationary part, and a moving part. In this second embodiment, the valve assembly may comprise a housing having an inlet and an outlet with the inlet forming one end of a tubular passageway. The valve member may comprise an inner stationary part and an outer moving part which can reciprocate along the inner stationary part. The outer moving part can be moved between a closed position where fluid is unable to flow through the valve assembly, and an open position. The outer moving part, when in the closed position, is substantially at the inlet of the valve assembly. The outer moving part may comprise a sliding cap. The inner stationary part may comprise an elongate peg or rod. The inner part typically has an outer end which is substantially at the inlet of the valve assembly, and an inner end which can be secured to the inside of the housing to fix the inner part in place. The outer part typically has a peripheral inside wall which is formed with a sealing surface to seal against a portion of the inner wall of the tubular passageway when the valve member is in the closed position. Preferably, the closed position is where the outer part is substantially at the inlet of the valve assembly and presents a substantially flush surface with the inlet. The outer part may be provided with a passageway or bore which can allow the outer part to be mounted to the inner part. The passageway is typically circular. When the valve member is in the closed position (typically when the outer part is adjacent the inlet) it is preferred that the inner part has a configuration which provides a sealing engagement with the passageway or bore in the outer part to prevent any fluid from passing through the valve assembly. The outer part can be pushed along the inner part to an open position where it is preferred that the configuration of the inner part is such that fluid can flow through the bore and through the valve assembly.
Suitably, the tubular passageway is formed with recesses at a position spaced away from the inlet such that when the outer member is in this part of the tubular passageway, fluid can pass between the outer member and the tubular passageway. The biasing means may comprise a helical spring extending about the inner part and functioning to bias the outer part towards the inlet.
In a third embodiment, the valve assembly comprises a single valve member which may comprise a head part and a stem part and the biasing means may comprise a helical spring about the stem part. In this embodiment, the head part may slide along the tubular passageway between a closed position where the head part is substantially at the inlet, and an open position where the head part is pushed downwardly along the tubular passageway. The tubular passageway may be provided with at least one recess spaced away from the inlet to facilitate fluid flow past the head part.